Interpretive Summary:
Natural, intact, freshwater ecosystems, and the habitat they support are relatively rare in the semi-arid southwest. The water supporting these systems is often in high demand for human or agriculture use. To address this conflict, natural scientists must evaluate how human water use decisions impact hydrologic regimes and the ecological systems this water supports. A broad foundation of natural science information is needed value ecological systems. The goal of this research is to incorporate hydrologic, vegetation, avian, and economic models into an integrated framework to determine the value of changes in ecological systems that result from changes in policy decisions (e.g. growth, pumping, irrigation) that affect hydrological conditions in freshwater riparian systems. We have developed a Decision Support System for the San Pedro River Region (SPRR) in Arizona that considers groundwater, stream flow, and riparian vegetation, as well as abundance, diversity, and distribution of birds within a protected area encompassing the San Pedro Riparian National Conservation Area (SPRNCA). In addition, we are developing a similar framework for the Middle Rio Grande of New Mexico (MRG). Distinct valuation studies are being conducted for each site. This research is novel in that it provides much more detailed scientific information for economic valuation models than is typically available.

Technical Abstract:
Conservation of freshwater systems is a paramount issue in the semi-arid Southwestern U.S. Over time, these systems have been degraded by anthropogenic activities and, more recently, are threatened by climate change. For water reallocation efforts to succeed in preserving these systems, a policy maker requires a clear understanding of the management options available and a means to evaluate these options. One potentially effective approach is a Decision Support System (DSS). For water management where ecosystem services are part of the decision-making criteria, a DSS should have the capability of evaluating management options through the use of a series of coupled physical and ecological models that generate ecosystems service outputs. These outputs can then be reflected as monetized societal values for purposes of analyzing management options. However, ecosystem service values generally remain unknown relative to market values for goods and services. A primary focus of this paper is the value of ecosystem services and how they are derived from a broad base of scientific information. A central tenet of our efforts is that ecosystem values are appropriately driven by sound scientific information and thus values and sound science are inextricably linked. We also focus on the process of transferring these values to other semi-arid areas.